A THERMOSTABLE ALKALINE BETA-1,3-GLUCANASE PRODUCED BY ALKALOPHILIC BACILLUS SP AG-430

Alkalophilic Bacillus sp. AG-430 was isolated from soil and found to produce an extracellular β-1,3-glucanase. This enzyme was purified by chromatography on DEAE-sepharose CL-6B, Sephadex G-75 and hydroxyapatite. The enzyme was extremely thermostable and lost only 10% of the original activity after incubation at 100°C for 10 min. The optimum temperature and pH for activity were 60°-65°C and 9-10, respectively. The molecular weight was estimated at about 35 000 on sodium dodecyl sulphate-polyacrylamide gel eletrophoresis and the pI was about 3.8. The enzyme hydrolysed laminaritetraose, but not laminaritriose, and the end-products detected in the hydrolysate were identified as glucose, laminaribiose and laminaritriose. The enzyme split laminarin at random and yielded glucose, laminaribiose, laminaritriose and higher oligosaccharides. The enzyme is a type of endo-β-1,3-glucanase. © 1990 Springer-Verlag.